add `__version__` to python module

[lgsmith]

Is your feature request related to a problem? Please describe

I just like to be able to check the software version from the python import, as opposed to querying conda or rooting around in an install dir. Makes reporting other issues easier too.

Describe the solution you'd like

Add a __version__ attribute to the python module, which is customary for python modules.

Describe alternatives you've considered

You can currently solve this problem with conda list | grep loos...

Additional context

None